1. Field of the Invention
The present invention relates to a backlight module and a display device having the same, and more particularly, to a backlight module with a thermal isolating layer and a display device having the same.
2. Description of the Prior Art
The demand for liquid crystal display (LCD) significantly increases due to advantages of thinner thickness, lighter weight, portability, and low radiation in comparison with the CRT display. One of the main components of the liquid crystal display is the backlight module. With the progress of LCD manufacture technology, the backlight module is developed to be thinner thickness, higher brightness, and lower cost. In order to maintain the competition ability of LCD in the future market, lots of efforts spend on developing or designing a backlight module of better performance.
FIG. 1 illustrates a conventional liquid crystal display device and a backlight module thereof. As shown in FIG. 1, the LCD panel 10 is disposed over the backlight module 30 and a frame 15 surrounds the display panel 10. For an edge-type backlight module, the backlight module 30 includes a holder 31, a light bar 32, and a light guide plate 33. The holder 31 includes a sidewall 51, a top plate 53, and a bottom plate 55. The top plate 53 and the bottom plate 55 respectively extend from the upper end and the lower end of the sidewall 51 to form a space. The light bar 32 consists of a printed circuit board and light emitting diodes. As shown in FIG. 1, the light bar 32 is positioned in the space defined by the holder 31. One end of the light guide plate 33 extends and is clamped between the top plate 53 and the bottom plate 55 of the holder 31. Light emitted from the light bar 32 can enter the light guide plate 33 through this end.
In the case of using the light bar 32 as the light source, the heat dissipation effect significantly affects the lifetime of the light emitting diodes. In order to improve the heat dissipation of the light emitting diode, in the design of FIG. 1, the length of the bottom plate 55 of the holder 31 is increased along the light guide plate 33. By increasing the area of the bottom plate 55, the heat dissipation effect of the bottom plate 55 is enhanced. However, in such a design, since the bottom plate 55 extends into the projection range of the display area 11 of the display panel 10, the heat is conducted to the display area 11 of the display panel 10 through the light guide plate 33 during heat dissipation by the bottom plate 55. Liquid crystal molecules are injected into the display area 11 of the display panel 10. When the liquid crystal molecules are influenced by the heat dissipated from the bottom plate 55, resulting in incomplete twist. Such incomplete twist causes leakage of light when the display area 11 is at dark state, and therefore inadvertently affects the overall performance of the liquid crystal display device.